Medical devices may be implanted in patients in a variety of different surgical procedures. In the treatment of spinal irregularities, for example, implants may be inserted within a space created by complete or partial removal of an intervertebral disc between adjacent vertebrae. One example of an implant that may be placed into the disc space of a patient's spine is a spacer that can maintain height of the spine and/or restore stability to the spine. Another example of an implant that can be placed into a patient's spine is an artificial disc that can replace the disc while maintaining vertebral height and also preserving mobility in the treated vertebral segment.
A spinal implant can be inserted into the patient using an anterior, lateral, or posterior approach. Combinations of these approaches (e.g., posterolateral) can also be used. In each of these approaches, the surgeon typically has little room to maneuver the implant to the desired location. In addition, while maneuvering the implant, the surgeon must use care to avoid organs, nerves, and other structures that could result in damage to the patient. Accordingly, insertion tool assemblies that can be used to position the implant in the patient should securely hold the implant without allowing articulation, e.g., flexion/extension, lateral bending or axial rotation. Further, the connection between the implant and the insertion tool assembly should be rigid enough for impaction when being used by the surgeon. In addition, the implant should be readily removed from the insertion tool assembly once it has been placed in the desired location within the patient.
Several different insertion tool assemblies have been used heretofore to position implants in a patient. For instance, one type of insertion tool assembly that has been used includes threaded connections for securing the implant to the holder. These threaded assemblies may also incorporate vertical grooves to further secure the implant. One drawback to threaded connections includes cross-threading and the resulting difficulties in placing the implant in the desired position. Another type of insertion tool assembly that has been used includes parallel vertical jaws for securing the implant to the assembly. These jaws may, for example, protrude into upper and lower keels on the implant. One drawback to the parallel jaws is that the jaws may have issues maintaining parallelism with regards to the upper and lower endplates in certain artificial discs.
Thus, there is a need for improved insertion tool assemblies that can securely hold the implant while placing the implant within the patient.